Friction tube anchors are known, in which connection for example reference can be made to U.S. Pat. No. 4,459,067 A and WO 2006/066 288 A.
Friction tube anchors are rock anchors which have a tube which is folded to the inside in the lengthwise direction and which is placed in a bore hole and expanded by increasing the pressure within the folded tube so that the outer surface of the tube adjoins the inner surface of the bore hole and thus fixes the anchor in the bore hole.
In the known friction tube anchor (compare FIG. 1) the front end of the expandable tube 1 is closed by an end casing 2. The tube 1 has a wall which is folded to the inside essentially over its entire length (omega-like) (FIG. 2). The back end of the tube 1, therefore the end which is adjacent to the opening of the bore hole (the outer end of the bore hole) extends through an anchor plate 3 and bears an inflation jacket 4 with an inflation hole 5. Via an adapter attached to the inflation jacket 4 pressurized fluid (especially water) is delivered into the interior of the tube 1, and the tube 1 is expanded as the lengthwise fold of the tube 1 is unfolded so that the friction tube anchor is fixed in the bore hole by friction and positive locking.
WO 2004/099571 A also discloses attaching screw bolts, for example eye bolts, to the outer end pieces of these friction tube anchors to accommodate loads.